scholarly journals Attachment on mortar surfaces by cyanobacterium Gloeocapsa PCC 73106 and sequestration of CO2 by microbially induced calcium carbonate

2021 ◽  
Author(s):  
Tingting Zhu ◽  
Mohamed Merroun ◽  
George Arhonditsis ◽  
Maria Dittrich
Keyword(s):  
Extracellular Polymeric Substances ◽  
Living Cells ◽  
Carbonate Precipitation ◽  
X Ray ◽  
Cell Coverage ◽  
Electron And Fluorescence Microscopy ◽  
Order Of Magnitude ◽  
Analysis Of Results ◽  
Microbially Induced Carbonate Precipitation ◽  
Scanning Electron

Cyanobacterial carbonate precipitation induced by cells and extracellular polymeric substances (EPS) enhances mortar durability. The percentage of cell/EPS attachment regulates the effectiveness of the mortar restoration. This study investigates the cell coverage on mortar and microbially induced carbonate precipitation. Statistical analysis of results from scanning electron and fluorescence microscopy shows that the cell coverage was higher in the presence of UV-killed cells than living cells. Cells preferably attached to cement paste than sand grains, with a difference of one order of magnitude. The energy-dispersive X-ray spectroscopy analyses and Raman mapping suggest cyanobacteria used atmospheric CO2 to precipitate carbonates.

scholarly journals Study On The Performance Of Carbonate-Mineralized Bacteria Combined With Eggshell For Immobilizing Pb and Cd in Water And Soil

2021 ◽  
Author(s):  
Ting Wei ◽  
Noman Yashir ◽  
Fengqiu An ◽  
Syed Asad Imtiaz ◽  
Xian Li ◽  
...  
Keyword(s):  
Cation Exchange Capacity ◽  
Exchange Capacity ◽  
Contaminated Water ◽  
Carbonate Precipitation ◽  
Bacterial Isolates ◽  
X Ray Diffraction ◽  
X Ray ◽  
Soil Enzymatic Activity ◽  
Microbially Induced Carbonate Precipitation ◽  
Eggshell Waste

Abstract Microbially induced carbonate precipitation (MICP) is an advanced bioremediation approach to remediate heavy metals (HMs) contaminated water and soil. In this study, metal tolerant urease-producing bacterial isolates, namely UR1, UR16, UR20 and UR21, were selected based on their urease activity. The efficiency of these isolates in water for Pb and Cd immobilization was explored. Our results revealed that UR21 had the highest removal rates of Pb (81.9%) and Cd (65.0%) in solution within 72 h through MICP. The scanning electron microscopy-energy dispersive x-ray and x-ray diffraction analysis confirmed the structure and the existence of PbCO3 and CdCO3 crystals in the precipitates. In addition, the strain UR21, in combination with urea/eggshell waste (EGS) or both, was further employed to investigate the effect of MICP on soil enzymatic activity, chemical fractions and bioavailability of Pb and Cd. The outcomes indicated that the applied treatments reduced the proportion of soluble-exchangeable Pb and Cd, resulted an increment in carbonated bound Pb and Cd in the soil. The DTPA extractable Pb and Cd was reduced by 29.2% and 25.2% with the treatment of UR21 + urea + EGS as compared to the control. Besides, the application of UR21 and EGS significantly increased the soil pH, cation exchange capacity, and enzyme activities. Our findings may provide a novel perceptive for an eco-friendly and sustainable approach to remediate heavy metal contaminated environment through a combination of metal-resistant ureolytic bacterial strain and EGS.

Mechanism of adsorption of ferric iron by extracellular polymeric substances (EPS) from a bacterium Acidiphilium sp.

2011 ◽  
Vol 64 (8) ◽  
pp. 1716-1722 ◽  
Author(s):  
J. M. Tapia ◽  
J. A. Muñoz ◽  
F. González ◽  
M. L. Blázquez ◽  
A. Ballester
Keyword(s):  
Microbial Fuel Cells ◽  
Extracellular Polymeric Substances ◽  
Ferric Iron ◽  
Sorption Isotherms ◽  
Sorption Process ◽  
X Ray Diffraction ◽  
Freundlich Model ◽  
X Ray ◽  
Potential Impact ◽  
Scanning Electron

The aim of this study was to assess the sorption of Fe(III) by extracellular polymeric substances (EPS) of the Acidiphilium 3.2Sup(5) bacterium, which has promising properties for use in microbial fuel cells (MFC). The EPS of A. 3.2Sup(5) was extracted using EDTA. The sorption isotherms were determined using aliquots of purified EPS. The exosubstances loaded with metal were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction spectroscopy (XRD) and Fourier transform infrared spectroscopy (FTIR). The sorption uptake approaches to 536.1 ± 26.6 mg Fe(III) (g EPS)−1 at an initial ferric concentration of 2.0 g l−1. The sorption of Fe(III) by EPS can be fitted to the Freundlich model. The sorption process produces hydrated iron (III) oxalate [Fe(OH)(C2O4) × 2H2O] by a reversible reaction (log K = 1.06 ± 0.16), indicating that a shift in the sorption of the cation can be easily achieved. Know the magnitude and form of iron sorption by EPS in MFC can foresee the potential impact on the metabolism of iron-reducing and iron-oxidazing bacteria and, therefore, on the feasibility of the system.

A Facile Method to Preparation of Amphiphilic Perylene Tetracarboxylic Diimide/ZnS Hybrid Nanocomposites and Improved Semiconducting Property

2014 ◽  
Vol 936 ◽  
pp. 295-299 ◽  
Author(s):  
Jin Gang Song ◽  
Hong Yan Wang ◽  
Nian Shuai An ◽  
Yan Li Chen
Keyword(s):  
Organic Semiconductors ◽  
Hybrid Nanocomposites ◽  
Organic Template ◽  
X Ray Diffraction ◽  
X Ray ◽  
Current Voltage ◽  
Order Of Magnitude ◽  
Zns Nanocrystals ◽  
Semiconducting Property ◽  
Scanning Electron

A self-assembled film of an amphiphilic perylene tetracarboxylic diimide derivative (N-hexane-N'-(1-phenyl-4-aminoethanol)-1,7-di (4-tert-butylphenoxy) perylene-3,4;9,10-tetracarboxylate diimide, HH-PDI) has been used as the organic template to produce the first example of monodispersed nanoparticles of HH-PDI/ZnS composites. The HH-PDI pure film and HH-PDI/ZnS nanocomposites were characterized by UV-vis absorption, X-ray diffraction (XRD), scanning electron microscopy (SEM) and current-voltage (I-V) measurements. Experimental results revealed the film crystallinity and general molecular order for HH-PDI molecules in the nanocomposites are improved effectively in comparison with those in the pure film due to the introduction of ZnS nanocrystals. The electrical conductivity of the HH-PDI/ZnS nanocomposites (6.6×10-5 S cm-1) is more than ca. 2 order of magnitude higher than that of (3.6×10-7 S cm-1). The present result provides an efficient way to improve the performance of organic semiconductors through introducing inorganic semiconducting nanocrystals.

Influence of Sodium Tartrate on the Precipitation of Magnesium Carbonate

2011 ◽  
Vol 233-235 ◽  
pp. 2687-2691
Author(s):  
Min Guo ◽  
Tan Guo ◽  
Quan Li ◽  
Zhi Jian Wu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Powder Diffraction ◽  
Reaction Temperature ◽  
Magnesium Carbonate ◽  
Carbonate Precipitation ◽  
Sodium Tartrate ◽  
X Ray ◽  
Product Weight ◽  
Scanning Electron

Magnesium carbonate precipitation by the reaction of MgCl2 with Na2CO3, using sodium tartrate as an additive was studied. The effects of sodium tartrate concentration, reaction temperature, and stirring speed on the precipitation were investigated comprehensively. Scanning electron microscopy (SEM) and X-ray powder diffraction methods were used to characterize the carbonate precipitate products. Sodium tartrate concentration, reaction temperature, and stirring speed have significant effects on the morphology of the carbonate products. Sodium tartrate has an inhibitive effect on the precipitation. The product weight decreases with the increase in the amount of sodium tartrate added, and with the increase in reaction temperature, but is almost irrelevant to the stirring speed. The products obtained at 25 and 50°C were all identified as nesquehonite. The experimental results show that the use of an additive would be an effective method to adjust the morphology of magnesium carbonate.

scholarly journals Pyrolusite Bioleaching by an Indigenous Acidithiobacillus sp KL3 Isolated from an Indonesian Sulfurous River Sediment

2019 ◽  
Vol 19 (3) ◽  
pp. 712
Author(s):  
Endah Retnaningrum ◽  
Wahyu Wilopo
Keyword(s):  
Extracellular Polymeric Substances ◽  
River Sediment ◽  
Reduction Potential ◽  
Cell Attachment ◽  
Manganese Concentration ◽  
X Ray ◽  
Ph Values ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Scanning Electron

The manganese bioleaching process of pyrolusite from Kliripan, Indonesia using Acidithiobacillus sp KL3 was investigated. The influence pulp densities of pyrolusite (0.01, 0.02, 0.03 and 0.05 g/cm3) on the bioleaching processes were studied for 16 days. The reduction on pH values, the increasing of oxidation-reduction potential (ORP), sulfate and manganese concentration were analyzed. The manganese bioleaching mechanism of pyrolusite by the strain was monitored using Scanning Electron Microscope-Energy Dispersive-X-ray Spectroscopy (SEM-EDX). The results indicated that 0.02 g/cm3 of pyrolusite was considered to be the optimal pulp density for manganese bioleaching process. During this process, pH values decreased, furthermore resulted in increasing of ORP, the concentration of sulfate and manganese. SEM-EDX analysis clearly showed the evidence of directly bacterial cell attachment into the surface of pyrolusite. Extracellular polymeric substances (EPSs) were further founded on that surface. Sulfur elemental was oxidized by the strain which was then confirmed of resulting in solubilized manganese.

scholarly journals Biomineralization of Carbonate Minerals Induced by the Halophilic Chromohalobacter israelensis under High Salt Concentrations: Implications for Natural Environments

2017 ◽  
Author(s):  
Zuozhen Han ◽  
Dan Li ◽  
Hui Zhao ◽  
Huaxiao Yan ◽  
Peiyuan Li
Keyword(s):  
Electron Microscopy ◽  
Extracellular Polymeric Substances ◽  
Ph Value ◽  
Halophilic Bacteria ◽  
High Salt ◽  
Energy Dispersive ◽  
Control Group ◽  
Carbonate Precipitation ◽  
Carbonate Minerals ◽  
X Ray

The mechanism underlying microbiologically induced carbonate precipitation have not been thoroughly characterized, although numerous scholars and experts have specifically investigated questions regarding minerals induced by bacteria. The study of the precipitation of carbonate minerals induced by halophilic bacteria has aroused wide concern. The present study aimed to investigate the characterization and process of biomineralization in high salt systems by a halophilic bacterium, Chromohalobacter israelensis strain LD532 (GenBank: KX766026), which was isolated from the Yinjiashan Saltern in China. Carbonate minerals induced by LD532 were investigated in several sets of comparative experiments that employed magnesium sulfate and magnesium chloride as Mg resources. Magnesium calcite and aragonite were induced by LD532 bacteria, whereas these minerals did not appear in the control group. The mineral phases, micromorphologies, and crystal structures were analysed using X-ray powder diffraction, scanning electron microscopy, and energy dispersive X-ray detection. The carbonic anhydrase and urease secreted by strain LD532 through metabolism increased the pH value of the liquid medium and promoted the process of carbonate precipitation. Further study using high resolution transmission electron microscopy, energy dispersive X-ray detection and analysis of ultrathin slices showed that the nucleation sites of carbonate minerals were located on extracellular polymeric substances and the membranes of intracellular vesicles of LD532 bacteria, which provided favourable conditions for the growth of carbonate mineral crystals. The morphologies and compositions of minerals formed in solutions of MgSO4 and MgCl2 display significant differences, indicating that different sources of Mg2+ may also affect the physiological and biochemical activities of microorganisms and thus mineral deposition. This study will be of some interest for the interpretation of carbonate biomineralization in natural salt environments and has some value as a reference in understanding sedimentary carbonates in ancient marine environments, such as tidal flats.

Synthesis and Study of 239Pu-Doped Ceramics Based on Zircon, (Zr,Pu)Sio4, and Hafnon, (Hf,Pu)SiO4

2000 ◽  
Vol 663 ◽  
Author(s):  
B.E. Burakov ◽  
E.B. Anderson ◽  
M.V. Zamoryanskay ◽  
M.A. Yagovkina ◽  
E.E. Strykanova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Pressing Method ◽  
Optimal Amount ◽  
X Ray ◽  
Mass Losses ◽  
Ceramic Samples ◽  
The Matrix ◽  
Order Of Magnitude ◽  
Scanning Electron

ABSTRACTZircon, ZrSiO4, as well as its Hf-analogue hafnon, HfSiO4, have been proposed for use as durable Pu host phases for the immobilization of weapons grade Pu and other actinides. Four samples of Pu-doped ceramics based on the zircon and hafnon structures were synthesized through sintering in air using precursors containing 5-6 and 10 wt% 239Pu. Synthesized ceramic samples were studied by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), microprobe method, MCC-1 leach test at 25 and 90°C. Inclusions of separated a PuO2phase in the matrix of zircon-based ceramic and presumably, (Pu,Hf)O2 phase in the hafnon-based ceramic were observed for samples obtained from precursors doped with 10 wt% Pu. No separated Pu-phases in significant amounts were identified in the matrices of both ceramics obtained from the precursors doped with 5-6 wt% Pu. It was found that normalized Pu mass losses (without correction on ceramic porosity) for samples doped with 10 wt% Pu which contain separated inclusions of PuO2 or (Pu,Hf)O2 after 14/28 days were approximately (in g/m2) - for zircon: 0.2/0.2 - at 90°C and 0.03/0.04 - at 25°C and for hafnon: 0.02/0.04 - at 90°C and 0.01/0.01 - at 25°C. The losses of Pu from samples doped with 5-6 wt% are 1-2 order of magnitude less. It was suggested that optimal amount of Pu which could be incorporated by zircon and hafnon lattices does not exceed 7 wt%. An important additional conclusion is that Pu- doped ceramic based on zircon or hafnon can be successfully fabricated excluding hot pressing method.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

Quantification of Silica Uptake by Alveolar Macrophages - An Emperical Scanning Electron Microprobe Method

1982 ◽  
Vol 40 ◽  
pp. 332-333
Author(s):  
V. V. Damiano ◽  
R. P. Daniele ◽  
H. T. Tucker ◽  
J. H. Dauber
Keyword(s):  
Quantitative Analysis ◽  
Alveolar Macrophages ◽  
Bulk Sample ◽  
Silica Particles ◽  
Empirical Method ◽  
Phagocytic Cells ◽  
Calibration Standards ◽  
X Ray ◽  
Accurate Quantitative Analysis ◽  
Scanning Electron

An important example of intracellular particles is encountered in silicosis where alveolar macrophages ingest inspired silica particles. The quantitation of the silica uptake by these cells may be a potentially useful method for monitoring silica exposure. Accurate quantitative analysis of ingested silica by phagocytic cells is difficult because the particles are frequently small, irregularly shaped and cannot be visualized within the cells. Semiquantitative methods which make use of particles of known size, shape and composition as calibration standards may be the most direct and simplest approach to undertake. The present paper describes an empirical method in which glass microspheres were used as a model to show how the ratio of the silicon Kα peak X-ray intensity from the microspheres to that of a bulk sample of the same composition correlated to the mass of the microsphere contained within the cell. Irregular shaped silica particles were also analyzed and a calibration curve was generated from these data.

Sign in / Sign up

Export Citation Format

Share Document